Fastener driving tool



July 13, 1965 A. LANGAS FASTENER DRIVING TOOL 2 Sheets-Sheet 1 FiledMarch 13, 1963 ale/ 421325.

July 13, 1965 A. LANGAS FASTENER DRIVING T001:

2 Sheets-Sheet 2 Filed March 13, 1963 United States Patent 3,194,324FASTENER DRIVING TOOL Arthur Langas, Chicago, lll., assignor to SignodeCorporation, a corporation of Delaware Filed Mar. 13, 1963, Ser. No.264,902 5 Claims. (Ql. 173-2) This invention relates to a fastenerdriving tool and, particularly, to a safety mechanism for preventingaccidental operation of the tool.

Fastener driving tools such as those that are pneumatically powered aregenerally controlled by a trigger operated valve mechanism thatregulates the flow of highpressure air to and from the driving member ofthe tool. These tools are used in a large number of industries such asfurniture, luggage, and construction.

Tools of this type are designed to respond very quickly, and thus caremust be taken to prevent them from being accidentally operated. Thesetools are used to drive fasteners such as nails, staples, and pins uponthe introduction of high-pressure fluid to a driving member. Thus, forall intents and purposes such a tool is a gun that shoots a fastenerinstead of a bullet into and through members that are to be fastenedtogether. Such a tool can obviously be a dangerous weapon in the handsof a careless, negligent, or playful operator. Unless the operatorexercises extreme caution when handling the tool, it could bemisdirected and fire a fastener other than into the work, which maydamage something or injure someone standing near the operator.

It is with the above possibility in mind that safety mechanisms havebeen developed to prevent fastener tools from being fired, unless thetool is placed nearby or in actual contact with one of the members to befastened. One such safety mechanism consists of a mechanical arrangementthat locks the trigger against movement unless a safety pin is placedagainst the work. This type of mechanism has the obvious disadvantage ofincreasing the amount of time it takes an operator to drive a givennumber of fasteners. Another mechanism that has been used to preventaccidental firing is a multiple valve assembly employing two valves inseries to control the flow of high-pressure fluid between the powersupply and the driving member. Both valves have to be operated before afastener would be driven. One valve is operated by the trigger and thesecond valve by the safety mechanism. This arrangement requires a largenumber of parts and is not fail-safe since if the valve operated by thesafety mechanism develops a leak, the tool is no longer safe and can befired by simply pulling the trigger.

In the two types of safety mechanisms discussed above, the members thatmust be actuatedto efliect operation of the tool are normally spaced atsome distance from the point at which the nail is driven, whichincreases the possibility of the fastener being fired into space.Furthermore, the mechanical arrangement does not allow the trip for thetool to permit the tool to fire the instant actuating member or safetytrip pin to serve as a bottom the safety trip pin engages the surfacethat is to be nailed or stapled.

In accordance with the present invention, there is provided a safetymechanism that will prevent the tool from being fired unless the exitend of the tool is located immediately adjacent the point at which thefastener is to be driven. The novel safety mechanism may also be used asa bottom trip for the tool. Also, the safety mechanism is fail-safe andrequires a minimum number of parts.

The safety mechanism embodying the present invention includes a safetytrip pin that is located immediately adjacent the point at which thefastener is driven,

which thus all but eliminates the possibility that a fastener will bedriven other than into the member that is to be fastened. The trip pincan also be used to control the movement of the valve regulating theflow of air to the driving piston and thus eliminate the need for theoperator to move the trigger each time a fastener is to be driven. Thisprovides for very fast action of the tool without any danger to anyonestanding near the tool. The novel con struction of the safety devicepermits it to be used with any conventional tool that is triggeroperated without requiring any modifications of the tool to which it isto be applied.

A tool of the type embodying the present invention is illustrated in theattached drawings. The particular tool disclosed is a pneumatic nailerbut as such it is merely exemplary of the family of tools to which thesafety mechanism can be attached. Generally speaking, the safety devicefunctions to control the movement of the trigger assembly provided foroperating the tool. The trigger assembly is designed so that unless thesafety trip pin located in the nose of the tool is moved by the memberto be fastened, the trigger is ineffective to move the valve to directair to the driving piston of the tool. The safety trip pin is located ina groove disposed parallel to and immediately adjacent the guidepassageway in the nose of the tool for the driving blade and thefastener and extends beyond the nose of the tool. The upper end of thesafety mechanism consists of a flange portion that controls the movementof a safety trigger lever that forms part of the trigger assembly. Thetrigger assembly will not operate to move the valve controlling the flowof air to the driver until the safety trigger lever is properlypositioned by the flange of the safety mechanism.

When the tool is first placed in contact with the member to be fastened,the trip pin is pushed back within the groove in the nose of the tool.This rearward movement of the trip pin moves the flange portion of thesafety mechanism against the free end of the safety trigger lever tolocate it so that pivotal movement of the trigger assembly moves thesafety trigger lever against the valve to fire the tool.

It can be appreciated that the trigger can be held in the on position bythe operator and the trip pin serves as the valve positioning mechanism.

The structure by which the above and other advantages of the inventionare attained will be described in the following specification, taken inconjunction with the accompanying drawings illustrating a preferredstructural embodiment of the invention, in which:

- FIGURE 1 is a cross-sectional View of a fastener driving toolincorporating the safety mechanism;

FIGURE 2 is a bottom view of the tool shown in FIG- URE 1;

FIGURE 3 is an enlarged sectional View of the actuating valve and safetytrigger assembly;

FIGURE 4 is a view taken along lines 44 of FIG- URE 3;

FIGURE 5 is a view, partially broken away, taken along lines 55 ofFIGURE 2;

FIGURE 6 is an outline view of the tool and a sectional View of thesafety mechanism with the trigger pulled and the safety mechanism out ofengagement with the members to be fastened;

FIGURE 7 is a view similar to FIGURE 6 in which the tool is in positionto be fired but the trigger has not been pulled; and

FIGURE 8 is a view similar to FIGURE 7 except that the trigger has beenpulled to position the control valve to fire the tool.

Referring first to FEGURE 1, there is illustrated a mailer housing 1having a body portion 2 that serves as a handle by which the operatormay. grasp andmanipm late the mailer. a storage chamber 3 into which airunder pressure from any suitable source is introduced through a hose 4and hose nipple 6 connected to one end of thelstorage cham her 3. 1 Atthe, other end of the housing 1' is a cylinder 7 in which a'drivingpiston 8 is slidably disposed. Se-

The handle portion is'cored to provide cured to the underside of piston8 is a nail driver 9 that 7 extends through a driver and nail guide 11wherein it engagesthe end nail 12} of an adhered rowof nails located ina magazine 13 secured to the nail housing 1. The housing 1 and nailmagazine 13 are interconnected by suitable fastening means. i a The flowof compressed air between the storage chamber 3 and the interior ofcylinder 7 above piston 8 is controlled by a diaphragm valve assembly 14that seats against the upper edge of the cylinder 7. The dia-l phragmassembly'is clamped betwee'nthe'cap 16 and the main portion of housing.1 and serves to block off the 'flowof compressed air between theannular chamber 17 surrounding cylinder 7 and in communication withstorage chamber 3 and the chamber 18 within the cylinder rim-V mediatelyabove piston 8. When the diaphragm assem bly14 is raised, thehigh-pressure air from chamber 17 enters chamber 18 and moves pistonsand driver 9 with a sharp, quick driving action against the nail 12 todrive 7 it into place.

The movement of-the diaphragm assembly 14 is controlled by a pilot'valve29 located in a boss defined by the housing 1., Asillustrated in FIGURE.3, the pilot valve 20 includesa valve housing 21 that has an inlet 22'in communication with thestorage chamber-3,. an outlet port 23 incommunication with passage 24 that leadsto the chamber 15;formed betweendiaphragm assembly '14 and cap 16, and an exhaust port 26. .The -flow1offluid between passage 24 and exhaust port 26 is controlled by a sleeve27 that is slidably disposed within'the'valve hous-;

ing 21 and positioned by'a valve member 28; .The valve member 28 islocated within the sleeve27 and when first i moved engages the sleeve 27to shut. oi? the fiow'of fluid A between the storage chamber 3 andoutlet port 23fand upon' further upward movement "biases: sleeve 27 awayfrom valve seat 29 surrounding exhaust port 26. to connect chamber 15andpassage 24 with exhaust port 26 .to vent chamber. 15. I I i i -Thevalve member 28 is connected at its lower end to plunger 30 and isnormally biased into the position shown in FIGURE 3 by a spring 32extending between plunger 30 and a wallot the valve housing. Extendingfrom the lower end of plunger 30' is a button 31.

Theposition of valve member 28 is controlled by the, operation ofvthesafetytrigger assembly 36 to be de.-

scribed in detail hereinafter. 'When the tool is to befired,

thevalve member 28 is moved upwardly by the triggerassembly '36 tofirst-block oh. the flow of air' from the;

storage chamber 3 tochamber 15 and then vent chamber 15 to atmosphere topermit the fluid under pressure" in chamber 17 to raise thediaphragm,;assem-bly 14 off its seat to enter chamber 18 and-acton theupp'ersurface of piston 8 to move it in a driving direction against anail 12. r

.. The trigger assembly '36 consists of a U-shaped trigger 7 member 37that is pivotally mountedqaboutpin38 thatpositioned "by" the safetymechanis'mj42lso-that pivotal: movement of the trigger assembly 36.?Wi11movef the lever 41- :into' contact with thebutton 31 to operate the?valve 29. This latter action willilo'ccur when-ithe lip '48i moves andholds the: free end 'of 'the llever .41 inlaposition; wherevalve-actuating:moVement of tri g r assembly-36] bringsnthe leven llinto contact" with"v alve button-31;

From theforegoing, it will be observed that numerous V variationsandmodifications mayheefiected .Without'de l I extends-through alignedopenings infianges 1a, 1b ex- 1 tending outwardly from housing l (seeFIGURE 2). Lo-' cated within the sidewalls of the trigger assembly andpivot-ally mounted to the endthereof opposite pin 38 by a pin 39 is asafety trigger leverAl. The lever 41, when positioned .by the safetymechanism described hereinafter,"

- functio'nsrto engage button 31 of valve Ztlfto effect open: ingmovement of the diaphragm-14. It is to, be noted that unless the safetytrigger lever is positioned by the safety mechanism, as describedhereinafter, the trigger. member 37 .will engage the tool housing beforeit can eifejct movement of valve button 31 (see FIGURE 6).

- tion is illustrated in FIGURE8. r 1

.The. satety'mechanism for preventing trigger lever 41. ,l

When the tool is placedin contactfwith the .work to be 1 fastenedasshown inFIGUREEfijthe .safety mechanism; is positioned so thatoperationof the trigger assembly to the position shown in FIGURES moves the valve20, to: drive a fastener into the work. 3 With the safetymech'an' nismin the position-shown in FIGURE 6, movement of the trigger. will beineffective toichange the positioniof the valve '20.

The safety;mechanism driver and nail guidell, The track 44- extends:parallel.

to the nail guide andis'locateddmmedialely adjacent The end :o'f'the-pin43-is' biased outwardly be- 1 yond theend ,ofthe guideaby a s-p'ring46:disposedin a thereto.

recess 10 formed .in the housing 1; The spring 46 is disposed aroundlanupstanding finger portion 47 of the safety. mechanism 42.l'lA;-portion1of,.the safetymechanis'm ex-- tends upwardly:alongsidefthe' headportion 'ofjthe. housa ing and isbent over; at itsupper; endtoform; an out; 1

wardly extending flange"48 that abuts the pin 49 whenthesafety mechanismis in itsfextended position. In this position, as shown in FIGURES .1and 6,- theqsafety trigger" lever 41 is free tolpivot about pin 39.-

. When the .nose of; the "tool is placed;

safety mechanism -'t 0 :the position shown? If. it is desired tocontinuously 0 without having to repeatedly phll; the trigger the safetytrip pin can be used as 'abottom,trip actua'tor; That is]v to -=say,thet rigg er can be held in the on fiposit ion and E the movement otthesafetyitrip'pin oi the safety mecha-j. I nism used to control theoperation bflv'alvellfl by movingthe safety Ltrigger leverg43about pinf39.-;

, While thetrigger lever 41 is shownas being res trained" betweenpin38T-and lip 48,:the invention is not limited to this construction; Itis notes sentialthatthe lever 41= I come into contact withjpin 38lduringthezfoperation'of the.

trigger assembly. It isonly necessary that theFlever 41 be partingyfrom'the. true spirit and scope joflthe invention.

For example, the invention is not limited to the particular '7 detailsof the valve mechanism} andany-valve capable of performingthe functionsotthe one. diselosed couldbe Otherchangesfcould be ma de in; the shapeandgdesignof some'ofi thecomponents of the k sjtructurahelementsillustrated." I'

substituted therefor.

j It is, of. course, intendedto'cover appended claims all suchmodifications asiall within the scope of the claims. g "'I claim:' i BV 1. In a pneumatic fastening -tool having a handle and ahead portiondisposed adjacentthereto in which is lo, cated a fastener driverassembly, means for controllinga-ccidental' operation of'the tool isillustrated in various positions in FIG-J URES 6, 7, and 8. i This,mechanism controls the actuation of the valve 25) by controlling themovement ofthe safety" 42 includes. a safety trip pin 43 2 I 'that isslid'ablydisposed' inla'track 44 formed in the crate the fastener toolthe operation of said fastener driver assembly including a valve means,a trigger assembly mounted under said handle and positioned to bemanipulated toward said handle to operate said valve means, said triggerassembly including a trigger member pivotally connected to said tool, alever pivotally mounted at one end to said trigger, a stop disposedadjacent the other end of said lever, a safety mechanism for positioningsaid lever to condition the trigger assembly to operate said valve uponmanipulation thereof, said safety mechanism including a portion adaptedto engage said other end of said lever to dispose it adjacent said stopwhen the tool is brought into contact with a surface into which afastener is to be driven.

2. A pneumatic fastening tool including a housing defining a handleportion and a head section disposed adjacent said handle containing afastener driver assembly, means for controlling the operation of saidfastener driver assembly including a valve means, a trigger assemblymounted under said handle and positioned to be manipulated toward saidhandle to operate said valve means, said trigger assembly including atrigger member pivotally connected to said tool, and a trigger leverpivotally mounted to one end of said trigger and adapted to engage saidvalve, a stop disposed adjacent the other end of said lever, a safetymechanism for positioning said lever adjacent the stop to position thelever to operate said valve upon manipulation thereof, said safetymechanism including a portion adapted to engage said other end of saidlever to move it toward said stop when the tool is brought into contactwith a surface into which a fastener is to be driven, and means forresiliently biasing said safety mechanism against said surface wherebywhen the tool is removed from said surface the safety mechanism willdisable the trigger lever from operating said valve.

3. In a fastener driving tool having driver means and means forcontrolling the movement of said driver means including valve means;trigger means for operating said valve means comprising a U-shapedtrigger member pivotally connected to said tool, a lever disposed withinsaid trigger member and pivotally connected at one end thereof to saidtrigger member and adapted to engage said valve means; and a safetymechanism for positioning said lever to condition said trigger meanswhen the tool is placed in contact with a surface into which a fasteneris to be driven, said safety mechanism including an abutment portionadapted to engage said lever to pivot it about its connection to thetrigger member to condition said trigger means whereby movement thereofwill effect movement of the valve to operate said driver means.

4. In a fastener driving too] including a housing containing drivermeans, said housing defining a longitudinal track adjacent said drivermeans, and means for controlling the movement of said driver meansincluding valve means; trigger means for operating said valve meanscomprising a U-shaped trigger member pivotally connected to said tool, alever disposed within said trigger member and pivotally connected to oneend thereof and adapted to engage said valve means; and a safetymechanism for positioning said lever to condition said trigger means,said safety mechanism including a trip member disposed in said track andextending beyond said housing to engage a surface into which a fasteneris to be driven and a lip portion adapted to engage the other end ofsaid lever, whereby when the tool is placed against said surface, thetrigger means will be effective to poistion the valve to operate saiddriver means.

5. A fastener driving tool as set forth in claim 4 including resilientmeans positioned between said housing and said safety mechanism tonormally position said safety mechanism out of engagament with saidlever whereby the tool cannot be fired until said safety mechanism ispositioned by contact with the surface into which a fastener is to bedriven.

References Cited by the Examiner UNITED STATES PATENTS 2,858,741 11/58Simpson 42-7O 3,011,169 12/61 Cast et a1. 144.4 3,056,965 10/62 Rogers1-44.4-

GRANVILLE Y. CUSTER, 111., Primary Examiner.

1. IN A PNEUMATIC FASTENING TOOL HAVING A HANDLE AND A HEAD PORTIONDISPOSED ADJACENT THERETO IN WHICH IS LOCATED A FASTENER DRIVERASSEMBLY, MEANS FOR CONTROLLING THE OPERATION OF SAID FASTENER DRIVERASSEMBLY INCLUDING A VALVE MEANS, A TRIGGER ASSEMBLY MOUNTED UNDER SAIDHANDLE AND POSITIONED TO BE MANIPULATED TOWARD SAID HANDLE TO OPERATESAID VALVE MEANS, SAID TRIGGER ASSEMBLY INCLUDING A TRIGGER MEMBERPIVOTALLY CONNECTED TO SAID TOOL, A LEVER PIVOTALLY MOUNTED AT ONE ENDTO SAID TRIGGER, A STOP DISPOSED ADJACENT THE OTHER END OF SAID LEVER, ASAFETY MECHANISM FOR POSITIONING SAID LEVER TO CONDITION THE TRIGGERASSEMBLY TO OPERATE SAID VALVE UPON MANIPULA-